CONSIDERATIONS CONCERNING

Eu-discoaster tamalisiKAMPTNER, 19671 THEODORIDIS,l983

Mary-Luz RODRIGUEZ-PINDADO and Jose-Abel FLORES
University of Salamanca.· Department of Geo;ogy
Area of Paleontology. 37008 Salamanca (Spain)

Kamptner (1967) describes the species D~coaA~~ ~amali4, a tetraradiated asterolith is the following way:
11 Der Kalkkiirper besteht aus vier zu einem orthogonalen Kreuz angeordneten Armen.
Diese sind durchwegs von gleicher Beschaffenheit. Vom Zentrum des Kreuzes an gerechnet, sindsie je 4,5 ~ lang. An ihrer Basis sind sie 1,2 p breit und ebenso hoch, verjUngen sich nach derPeripherie und endigen mit einer ! p breiten gerundeten Spitze. Von der Seite gesehen, erscheint
das Profil des KalkkHrpers nach Art eines schmelen Sichelmondes gekrummt, wobei die Oberseite
sich Uber die durch die Armspitzen gedachte Basislinie auf 2,7 p erhebt. Die Oberseite des Kalkkorpers entbehrt jeglicher Skulpturen; vor allem sind in der Basalregion de~ Arme keinerlei
Grenzlinien zwischen diesen wahrzunehmen".

Hay (1970) concluded that he was dealing with a subespecies ofDi../.Jcoa/.)~~ b/l.oUllHVU. Tan, and denomi riated it D. b/l.ouwrvU... ~ama.-L.iA Kamptner.
Theodoridis (1984) considers it as a "morpho.logical variety" cif the same sp!
cies* -D.b/l.ouw~- although in many works other· authors.have considered it
to be a separate entity (Perch Nielsen, 1977; Dermitzakis and Theodoridis,1978; Haq and Berggren, 1978; Moshkovitz and Ehrlich, 1980 and Driever, 1981).
Backman and Shackleton (i983) and Backman and Pestiaux (1983),
studying different DSDP sites in the Pacific and Mid Pliocene of the Atlantic, observed covariation between the species D.~ama.-L.iA and Di../.JcoaA~~ aA!J.mmei/l.i..cu/.J • These authors suggested the possibility that the model might befound at global level and that a certain taxonomic relationship could exist
between the two species.
At site 397 of the NW Atlantic it is possible to find represent~
tives of cu-di/.JcoaA~eA ~amaii4*as from core 31 while from core 22 onwards aclear remission in its recording is seen kO.Ol%). According to Hamilton(1979), the first event would be situated on the boundary between the Gilbert
and Gauss m~gnetic epochs, while second occurs towards the beginning of the~ See appendix

INA Newsletter vo1.10- 1988

38

Matuyama epoch. As may be seen in figure l, the quantitative model of thedistribution of c. -tama.h..4 is similar to that of c. a/.Jymme:t/U..CJ..Vj, in contrast
to that of c. b~o~
The fact that forms with peculiar characteristics (tetraradiated,with tetragonal symmetry, and lacking surface ornamentation) appear over aparticular period of time (end of Lower Pliocene and Upper Pliocene) in a r!
gular fashio~*,suggest to us that they should be considered as separate e~tities, although it should be taken into account that their status as a 11 bio
logical species .. might not be absolutely correct. In other words, it would
not be possible to rule out the notion that one were dealing with an ecophe_
notype resulting from environmental variations.

1250....

ISOI 75

p~

FIGURE 1.
Quantitative distribution of three sp~
cies of asteroliths in site 397, dur1ng
the Pliocene.

0200~

L

Reduction in the regular record ofc. quinquMUJ71U4[£] Earliest ·record of Ce~a.tv.hUtu->~ Latest record of C.acu~->

EB Earliest record of c.

225

-o

250

0 Reduction in the proportion ofrp_ 1acww-1a~0~:§2 75.s;;.

10JE9.jJ

0.

"0tama~i->

Increase in the proportion ofE.. iamal<~->Reduction in the proportion ofasteroliths

clOO

E325

N
350

375-m

400

I-0.1 X-o0**FLORES (in. prep,) found tetraradiated forms in low proportion in the Upper Tortonianand Messinian from different DSDP sites (397, 135 and 410).

---------------------------INA Newsletter vol.10- 1988
39

In view of all of the above, and following the systematic model
proposed by Theodoridis (1984), the denomination cu-cLi..-1coaA:tvz. :tamaA..-i.A, as
Theodoridis him self proposed in 1983, seems feasible.

APPENDIX
Theodoridis (1984) considers Oi~coaA:te~ :tam~Kamptner, synonymous to cu-cLi..-1coaA:tvz. O~OUJl)e.ll.i... subspec. O~QU/1)~ 'although previously' in

his paper of 1983 cites:cu-cLi..-1coaA:tvz. :tam~ (Kamptner) n. comb.
Basionym: DiAcoaA:tvz. :tam~iA Kamptner, 1967: Ann. Naturhist.
Mus. Wien, vol. 71, p. 166, text-fig. 29.

REFERENCES.-

8ACKMAN, J. and PESTIAUX, D. 1983. Pliocene Discoaster abundance variations, Deep Sea Drilling
Project Site 505: Biochronology and Paleoenvironmental implications. !nit. Rep.
DSDP, 94(2): 903-910
8ACKMAN, J. and SHi!.CKLEfON, N.J. 1983. Quantitative biochronology of Pliocene and. early Pleistocene calcareous nannofossils from the Atlantic, Indian and Pacific oceans. Mar •.
Micropaleontol., 8: 141-171
DERMITZAKIS, M.D. and THEODORIDIS, S.A~ 1978. Planktonic foraminifera and calcareous nannoplank
ton from the Pliocene of Konfonisi Islands (East Crete, Greece). Ann. Geol. Pay;
Hell en., ser. I, 29 (2): 630-643
DRIEVER, 8.V.H. 1981. A quantitative study of Pliocene associations Oiscoaster from the Mediterranean. Proc. Konink. Neaderlandse Ak. Wetenschopper, 8 84, 4: 437-455
HAMILTON, N. 1979. A paleomagnetic study of sediments from site 397 Northwest African Contina~tal margin. !nit. Rep. DSDP, 41(7): 463-477
HAQ, B.U. and BERGGREN, W.A. 1978. Late neogene calcareous plankton biochronology of the Rio
Grande Rise (Sout~ Atlantic Ocean). J. Paleontol., 52(5): 1157-1194
HAY, W.W. 1970. calcareous nannofossils from cores recordered in Leg 4. !nit. Rep. DSDP, 4:455-501
KAMPTNER, E. 1957. Kalkflagellaten-Skelettreste aus Tiefseenchlamm des Sudatlantischen Ozeans.
Ann. Naturhist. ~us Wien, 71: 117-198~OSHKOVITZ,

S. and EHRLICH, A. 1980. Dfstribution of the calcareous nannofossils in the Neogeneseq~ence of the Jaf.fa-1 borehole, Central Coastal Plain, Israel. Bull. Geol. Suvr.
Israel. PD/1/8

PERCH-NIELSEN, K. 1977. Albian to Pleistocene calcareous nannofossils fron the Western South
Atlantic, DSDP Leg 39. !nit. Rep. DSDP, 39: 699-823
THECDORIDIS, S.A. 1983. On the legeti~acy of the generic name Discoaster Tan, 1927 ex Tan, 1931
INA newsletter, 5: 15-21
THEODORIDIS, S.A. 1984. Calcareous nannofossil biozonation of thr Miocene and revision of thehelicoliths and discoasters. Utrecht Micropal. Bull., 32: 1-271

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